目的:为验证太赫兹二维阵列成像实现尺寸测量的可行性,对太赫兹二维成像系统进行标定.方法:设计一种适合太赫兹相机标定的透射成像模型,通过圆孔标定板,实现内外参数计算并对图像进行畸变校正,基于校正后的图像完成像素当量标定.结果:相机标定中特征像点经标定后成像坐标与实际对应像点坐标偏差的均方根为0.195 8 pixel,像素当量标定重复性数据方差为0.000 185.均方根值小于0.20 pixel,验证了透射成像模型的可行性;像素当量重复性数据方差接近于0.结论:标定方法稳定可靠,进而验证了太赫兹二维阵列成像实现尺寸测量的可行性.
Aims:To verify the feasibility of terahertz two-dimensional array imaging for dimensional measurement,a terahertz two-dimensional imaging system was calibrated.Methods:A transmission imaging model suitable for terahertz camera calibration was designed.Through a circular hole calibration plate,the internal and the external parameters were calculated;and image distortion was corrected.Pixel equivalent calibration was completed based on the corrected image.Results:In camera calibration,the root mean square of the deviation between the calibrated imaging coordinates of the feature image points and the actual corresponding image point coordinates was 0.195 8 pixels;and the pixel equivalent calibration repeatability data variance was 0.000 185.The root mean square value was less than 0.2 pixel,which verified the feasibility of the transmission imaging model.The pixel equivalent repeatability data variance was close to zero.Conclusions:Thecalibration method is stable and reliable.The dimensional measurement by Terahertz two-dimensional array imaging is feasible.